The invention relates to a new construction of a light emitting diode array, dot matrix or segmented display and a method for forming the same.
A conventional light emitting diode array, dot matrix or segmented display generally consists of a white and reflective display with many holes filled with diffusion epoxy. A circuit board adheres to the bottom of the display and each light emitting chip of the circuit board is kept exactly at the center of the hole where the resin epoxy has the function of insulating and diffusing the light from the chip. However, the display is not allowed to have any impurity or bubble; otherwise, the light intensity become uneven.
As the light emitted by the light emitting chip cannot be entirely reflected by the wall of the hole, quite a bit of light will penetrate and diffuse around the hole wall, and the light of the surface between the holes is dimmed. In order to correct such drawbacks and to strengthen visual contrast between the hole and the display, the display surface, according to conventional manufacturing art, must be printed with opaque printing ink to shield the dim light inside the surface. (so-called light leak or diaphaneity)
As the adjacent displays are not combined tightly during combination, the side of one display is usually higher than the adjacent display. Therefore, its display effectiveness is reduced. For a high-quality reflector, it is necessary to print non-transparent printing ink on the sides of the display, i.e. the five faces of the display must be printed by turns.
A flow chart of manufacturing light emitting diode (LED) display by traditional method is shown in FIG. 1A. (See Appendix at the end of the Specification.)
Obviously, the process of manufacturing conventional LED display is rather tedious, and since there is a big difference in the time for the various operations, bottlenecks occur in the production line and the efficiency of the production is very difficult to upgrade. Furthermore, during the process of filling resin into the display holes, it is very difficult to get rid of bubbles or impurities in the resin that affect the light intensity in the LED display. During inspection after manufacture, if it is discovered that the light intensity of a chip in one hole is different from that in other holes, no disassembly or correction is possible because the resin has hardened in the holes and the chip on the circuit board has adhered firmly with it. Consequently, the whole product has to be discarded and the various parts cannot be reused.